update your stb with loader. if not ok: protected memory is the problem.
There are two solutions. the best solution is to update stb with modified file(by CPU_CORE).
ex: i have gn2500 with menu: FOREVER.HD9520PVR, or: IStar30000, MC-8800, SR-8800HD, SR-9000HD, SR_X9990HD,TIGER800.
(serial function hacked)